Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R25/00—Fittings or systems for preventing or indicating unauthorised use or theft of vehicles
  • B60R25/20—Means to switch the anti-theft system on or off
  • B60R25/24—Means to switch the anti-theft system on or off using electronic identifiers containing a code not memorised by the user
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
  • G07C9/00—Individual registration on entry or exit
  • G07C9/00174—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
  • G07C9/00309—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R25/00—Fittings or systems for preventing or indicating unauthorised use or theft of vehicles
  • B60R25/30—Detection related to theft or to other events relevant to anti-theft systems
  • B60R25/34—Detection related to theft or to other events relevant to anti-theft systems of conditions of vehicle components, e.g. of windows, door locks or gear selectors
• • E—FIXED CONSTRUCTIONS
  • E05—LOCKS; KEYS; WINDOW OR DOOR FITTINGS; SAFES
  • E05B—LOCKS; ACCESSORIES THEREFOR; HANDCUFFS
  • E05B49/00—Electric permutation locks; Circuits therefor ; Mechanical aspects of electronic locks; Mechanical keys therefor
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
  • G07C9/00—Individual registration on entry or exit
  • G07C9/00174—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
  • G07C2009/00753—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by active electrical keys
  • G07C2009/00769—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by active electrical keys with data transmission performed by wireless means
  • G07C2009/00777—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by active electrical keys with data transmission performed by wireless means by induction
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S70/00—Locks
  • Y10S70/46—Conducting key

Definitions

• the invention relates to an anti-theft system for a Motor vehicle. It particularly concerns a locking system for doors of a motor vehicle and an immobilizer, by which enables the engine to start if authorized.
• a known anti-theft system (US 4,918,955) has Ignition lock with a transmission antenna in the form of a coil. The coil is excited by an oscillator. The ignition key has an oscillating circuit which interacts with the transmitter coil. Once the ignition key is inserted into the ignition lock is coded information from the ignition key transferred to the castle. If the encoded information matches a target code information, a Immobilizer released in the motor vehicle, so that the motor vehicle can be started.
• the problem of the invention is an anti-theft system to create through the despite component tolerances and temperature influences a safe operation of doors or a Starting the motor vehicle is possible.
• a stationary transmitter points in a lock on an oscillating circuit, the one with an oscillating circuit of a portable transponder coupled in a key is.
• An oscillation is forced in the transmitter Energy is transmitted to the transponder, which in turn transmits coded data back to the transmitter.
• the code information of the transponder modulates the vibration of the Transmitter resonant circuit in its amplitude.
• a demodulator wins the code information from the modulated vibration, compares it with target code information and if it matches an enable signal is generated.
• the modulated vibration scanned again the sampling time being a predetermined Phase angle is shifted compared to the sampling time the first time the code signal is detected.
• An anti-theft system has a stationary one Transceiver 1 (Figure 1) in a lock that with a portable transponder 2 in an ignition or door key interacts via a transformer coupling if the transponder 2 is located near the transceiver 1.
• the transceiver 1 transmits energy to the transponder 2 (For this reason, the transceiver is hereinafter referred to as the transmitter 1).
• Code information stored in the transponder 2 are retransmitted to transmitter 1 (Energy transmission and data retransmission are through one dotted double arrow shown).
• the transmitter 1 has a transmitter coil 11 which is wound, for example, around the ignition lock or the door lock.
• the transmitter coil 11 forms, together with a transmitter capacitor 12, a transmitter resonant circuit.
• the transmitter resonant circuit is fed by an alternator or an oscillator 13 with an alternating voltage or alternating current in time with its oscillator frequency f O and excited to oscillate.
• the field excited by the transmitter coil 11 induces a voltage in a transponder coil 21 if it is inductively coupled to the transmitter coil 11. This is the case, for example, when the key is inserted into the lock.
• the transponder 2 has a load switch 22 which is in the Clock of a predetermined and stored in the transponder 2 Code information between two different load resistors 23 and 24 switches back and forth. Since the two coils 11 and 21 are inductively coupled (such as primary and Secondary coil of a transformer), becomes the transmitter resonant circuit through the transponder resonant circuit in the rhythm of the code information charged. Consequently, the code information is on transmit the transmitter 1. There it is processed by an evaluation unit 3 recorded and evaluated.
• the evaluation unit 3 has a demodulator 31, the the voltage between the transmitter coil 11 and the transmitter capacitor 12 taps and an amplifier and one Low pass to a sample and hold element not shown in FIG. 1 34 ( Figure 7) passes on.
• the transponder 2 has an oscillating circuit with the transponder coil 21, a transponder capacitor 25 and the two Load resistors 23 and 24.
• the load resistors 23 and 24 are generated by a code generator, not shown Load switch 22 alternating in rhythm with the code information connected to the transponder resonant circuit. This will make the Transmitter resonant circuit loaded in the rhythm of the code information. There may also be several different load resistors his.
• the code information is in a memory, not shown of the transponder 2, for example a ROM or EEPROM.
• the code information can also be hardware-based the transponder 2 may be included. It is for the invention however insignificant, like the code information in the transponder 2 included and how it is transmitted to the transmitter 1.
• the transmitter resonant circuit oscillates at the excitation frequency is predetermined by the oscillator 13. If the ignition key is inserted into the ignition lock, so there are Transmitter coil 11 and the transponder coil 21 in the immediate vicinity Closeness to each other. As a result, the two coils 11 and 21 are inductively coupled to one another such that the code information word is transmitted to the transmitter resonant circuit, i.e. the Vibration of the transmitter resonant circuit is affected ( Figure 2).
• the transmitter resonant circuit is load modulated, namely in the clock as between the load resistors 23 and 24 back and forth is switched.
• the load modulation corresponds to an amplitude modulation ( Figure 2).
• the frequency of the vibration changes through the burden is not.
• the vibration is loaded the first load resistor 23 or 24 the transmitter resonant circuit and in the following section B the other one is charged Load resistor 24 or 23 the transmitter resonant circuit.
• a section consists of several periods, each with identical, consecutive vibration trains with each same period T and same amplitude.
• To one section A or B changes the amplitude and the phase of vibration. Representing the whole Vibration will therefore become an oscillation A during a period in section A and a vibration B viewed in Section B during a period.
• the code information of transponder 2 is included.
• the Evaluation unit 3 filters this code information from the modulated one Vibration out, i.e. the amplitudes of the modulated Vibrations are measured and evaluated.
• This code information is digitized and in a digital Computing unit 37 with stored target code information compared. If the two code information match, a release signal is sent to a safety unit 38 sent, which generates a control signal.
• the time course of sinusoidal quantities (FIG. 3b) is usually represented in a coordinate system in which the time t or the angular frequency ⁇ t is plotted on the x-axis and the amplitude is plotted on the y-axis.
• An instantaneous value of a sinusoidal voltage u or a current i is uniquely determined by two quantities, namely the amplitude û and the phase ⁇ at a certain frequency f. To illustrate such variables, they are usually represented in a pointer diagram on the complex level (FIG. 3a).
• the real part Re is plotted on the x-axis and the imaginary part Im on the y-axis.
• the instantaneous value is then represented as a complex pointer u or i with a specific length and a specific phase ⁇ .
• the underscore u or i illustrates the complex size.
• the voltage u is phase-shifted by the phase angle ⁇ with respect to the current i.
• the modulated vibration is in the sections A and B are shown for a period T each (see Figure 2).
• the vibration A becomes due to the load by the first load resistor 23 or 24 and the vibration B due to the load by the second load resistor 24 or 23 caused.
• the two vibrations A and B occur in reality not at the same time, but are in successive sections, as in FIG. 2 shown.
• the vibrations are for better illustration A and B shown in Figure 4 one above the other, wherein the two vibrations A and B differ in their amplitude and out of phase with each other by the phase angle ⁇ are.
• the modulated vibration can be repeated several times within a period or once can be scanned within several periods.
• the sampling time is dimensioned accordingly by all involved components and is therefore subject to certain Fluctuations caused by component tolerances or temperature changes caused.
• FIG. 5a shows two pointers, namely those of the real part of the two oscillations A and B at a sampling time shown.
• the lengths differ the pointer by a certain amount, i.e. distinguish the real parts itself and code information can be obtained.
• the special case occurs that the real parts are the same (FIG. 5b), the code information cannot be obtained because there is no difference despite modulated vibration is recognized in the amplitudes. This can be due to component tolerances or temperature influence, because that Theft protection system is dimensioned by the manufacturer so that under normal conditions there is always code information obtained when the modulated vibration is first sampled becomes.
• the modulated vibration is according to the invention sampled again by a phase angle ⁇ 1 postponed.
• the renewed scanning is shown in FIG. 6 and corresponds to a rotation of the coordinate system around the phase angle ⁇ 1. From Figure 6 it can be seen that in the phase shifted by the phase angle ⁇ 1 a difference between the two amplitudes is detected and get the code information from the modulated vibration can be.
• FIG. 7 is a block diagram of the invention Anti-theft system shown.
• the oscillator 13 forces with its oscillator oscillation an oscillation equal Frequency in the transmitter resonant circuit, due to the approach of the transponder 2 to the transmitter resonant circuit becomes.
• the modulated signal is transmitted via a Amplifier 32 and a low pass 33 to a sample and hold 34 led where the value of the signal at the given time t0 is measured and held for a short time.
• the sampled signal is smoothed and fed to a Schmitt trigger 36, which smoothed the Signal into a square-wave signal for the computing unit 37 changes.
• the oscillator oscillation is also the computing unit 37 supplied as a reference or synchronization signal. Consequently can the sample and hold member 34 in synchronism with the excitation vibration are controlled by the computing unit 37. So that results a fixed reference point on which all sampling times are related. This also ensures that the modulated vibration within each period always at is sampled at the same time.
• the modulated signal becomes a predetermined one Time sampled, for example at t0. Is already too noticed a difference in the amplitudes at that time, there is evaluable code information. This code information is then compared with a target code information, the manufacturer's in a memory of the computing unit 37 is saved. If the two code signals match, the transponder 2 is authorized to unlock doors or to release the immobilizer. A release signal will then appear generated and fed to the safety unit 38.
• FIG. 8 shows an exemplary embodiment of a circuit arrangement the anti-theft system according to the invention shown.
• the components from the block diagram according to FIG. 7 are drawn with dashed lines in FIG.
• the modulated vibration can also be scanned in such a way that at least two voltage values within each period the vibrations A and B are detected. Doing so however, the sampling instants each around the phase angle jeweils1 be shifted to each other. These voltage values can be the Arithmetic unit 37 fed and evaluated there. If no code information available from the first voltage value the next voltage value is used.
• the computing unit 37 can be a microprocessor or a functionally equivalent unit can be realized.
• the security unit can be a door lock or be part of an immobilizer. Under an immobilizer such electronic devices are to be understood in the motor vehicle, which only starts the engine if authorization is given enable.
• the engine control can ON / OFF valve in the fuel line or a switch be referred to as a safety unit in the ignition circuit.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Lock And Its Accessories (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (2)

Family

ID=8216440

Family Applications (1)

Country Status (4)

Cited By (9)

Families Citing this family (25)

Citations (4)

Family Cites Families (5)

• 1994
  • 1994-11-07 EP EP94117526A patent/EP0710756B1/fr not_active Expired - Lifetime
  • 1994-11-07 DE DE59409716T patent/DE59409716D1/de not_active Expired - Fee Related
• 1995
  • 1995-11-07 US US08/554,821 patent/US5616966A/en not_active Expired - Fee Related
  • 1995-11-07 KR KR1019950040022A patent/KR100390075B1/ko not_active IP Right Cessation

Patent Citations (4)

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